Commit 181da0c3 authored by simonpj's avatar simonpj
Browse files

[project @ 1999-06-30 09:49:55 by simonpj]

Add a test for deriving Show (f (f a)); makes Hugs hang
parent 6f7e6ae4
{- From: Ian Bayley
Sent: Tuesday, June 29, 1999 3:39 PM
Subject: Show for higher-order nested datatypes
Is "deriving Show" meant to work for higher-order nested datatypes ?
Hugs hangs when loading in the following file:
module Foo where
type SqMat a = SM Nil a
data SM f a = ZeroS (f (f a)) | SuccS (SM (Cons f) a)
deriving Show
data Nil a = MkNil deriving Show
data Cons f a = MkCons a (f a)
deriving Show
No instance for `Show (f (f a))'
When deriving classes for `SM'
Compilation had errors
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